Crane



July 5, 1932 R. w. KALTENBACH 1,865,762

CRANE Filed Nov. 1l, 1929 2 Sheets--Sheel l SWW/nto@ @www July 5, 1932 R. w. KALTENBACH CRANE Filed Nov. l1. 1929 2 Sheets-Sheec 2 :Fl Gr.42'

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Patented July 5, 1932 UNIT STATES ROBERT W. KALTENBACH, OF CLEVELAND HEIGHTS, OHIO CRANE Application filed November 11, 1929.

This invention relates to cranes, and particularly to those which are known as shipbuilding or hammerhead cranes, and which are generally identified by a tower either stationary or movable, which carries a rotating boom along which a trolley is arranged to travel. rIhe mechanism for rotating the boom usually comprises an electric motor which is mounted on the boom and which is operatively connected to a pinion that extends downwardly from the boom and adj acent the tower. A circular rack in the form of a ring gear is Jfastened to the tower and is arranged to mesh with the pinion. rI`he boom is normally supported on top of the tower by the assistance of a pintle which extends downwardly from the boom and into the tower, and which absorbs stresses incident to shifting of the load along the boom. I have found that the shifting of the center of gravity, incident to the shifting of the load causes slight lateral movement of the axis of the pinion with reference to the axis of the circular rack, and that in some cases the D movement is so pronounced, due to wear of the pintle rollers, as to cause the pinion to become disengaged from the rack.

The principal object of the present invention, therefore, is to provide a mechanism which will retain the desirable characteristics of the boom mounting for the turning mechanism, and yet will eliminate the possibility of disengagement between the pinion p and rack. In this connection, my invention is directed toward a mechanism which is simple in construction and which can readily be incorporated in the construction of existing cranes.

Referring to the drawings, Fig. 1 is a side elevation of a crane embodying my invention; Fi 2 is a. horizontal section taken on a plane in icated by the line 2-2 in Fig. 1, and Fig. 3 is a vertical section taken on the line 3-3 of Fig. 2.

The crane, in general, has a supporting frame or tower 10, and an elongated boom 11, which is mounted for rotation on the tower. A trolley is indicated, in general at 12, and is arranged to move along along tracks which are carried on the, boom in the Serial No. 406,233.

usual way. A guiding beam or pintle, as indicated at 15, is a fabricated structure, which is rigidly attached to the boom and which extends downwardly within the tower. rlhe lower end of the Dintle is provided with a thrust bearing, indicated in general at 16, in Fig. 1 while the upper end, as 'shown in Fig. 2, has rollers 17 which engage a circular trackway 18 on the extreme inner periphery of the circular rack 19. Such rack is rigidly mounted on the tower, and is arranged o mesh with gearing on the boom for effect-V ing rotation thereof.

The mechanism, which I employ for providing an operative connection between the boom and the rack comprises a pinion 20, which is rigidly mounted on 'the lower end of a vertical shaft 21, which in turn extends downwardly from the boom and near the rack. An electric motor, indicated in general at 22 in Fig. 1, is suitably geared to the shaft 21 for effecting rotation thereof. In Fig. 3, the shaft 21 is shown as being journaled to a supporting member 23, which in turn is aliXe-d to the boom. The pinion 20 is relatively near the rack but is not in mesh therewith.

To make an operative connection between the pinion and the rack, I provide an idler gear 25, which is arranged to mesh simultaneously with the pinion and with the rack. The mounting for the idler is designed to ermit a slight relative movement between the axis of the shaft 21 and the axis of the rack without in anyway affecting the operativeness of the driving connection. To this end, a slotted member extends across and above theidler and rack, and provides a support for a pin 31 on which the idler is journaled. The member 30 also provides a journal for shafts 35, which extend vertically therethrough and which carry rollers 36 at the lower ends thereof. These rollers are then arranged to move in a channel-shaped annular trackway 37, which is disposed inside the rack teeth.

To provide a supporting connection between the idler and the driving shaft, I have shown a link 40 which extends into the slot 41 of the member 30, and is arranged to extend around the supporting member 23. In practice, this link preferably comprises two parts which are suitably fastened together by securing members l2 and 43. Such securing members when tightened hold the two parts together, yet permit the idler and its associated supporting mechanism to move in a circular path about the axis of the shaft 2l whenever the boom is moved longitudinally of itself and with reference to the tower. Thus, the pitch alignment between the pinion and idler, and the pitch alignment between the idler and rack is maintained even though the boomv mayl shift longitudinally of itself and with reference to the tower. As the member 30 may be swiveled upon the member 23, it is obvious that the boom may shift an amount equal to approximately half the diameter of the idler gear. In practice, however, such degree of movement would not occur but it is apparent that pitch alignment is maintained at all times within the degree of practical movement.

By means of my invention, I have been able to maintain the desirableV characteristics of the pinion and rack connection for effecting rotation of the boom with reference to the tower, and yet have eliminated the possibility of disengagemei'it occurring between the pinion and rack, whenever the boom shifts a relatively small amount longitudinally of itself and with reference to the tower. Furthermore, I have provided a relatively simple mechanism by which this result may be obtained, and I have made a construction which can readily be attached to existing cranes.

I claim:

l. A driving means for cranes and the like, comprising in combination, a relatively stationary circular rack, a turntable, a gear rotatably mounted on the turntable, an idler gear in mesh with the first named gear and with the rack, and means guided by the rack for maintaining the pitch alignment between the idler gear and the rack, and between the idler gear and the driving gear, notwithstanding variations in the distance between the axis of the driving gear and the rack.

2. In combination, a supporting member, a turntable thereon, a circular rack carried by one of the members, a pinion rotatably mounted on the other of said members, means mounted on one of said members for operating the pinion, an idler gear providing an operative connection between the raclr and pinion, and means extending across and revoluble on the rack for supporting the pinion with reference to the idler gear, whereby a fixed relationship is maintained between the axis of the idler gear and the axis of the rack, while a variable relationship exists between the axis of the pinion and the axis of the rack.

3. A driving connection between a pinion,

and a circular rack comprising in combination, an idler gear in mesh with the pinion and rack, a circular trackway on the rack, and a support for the gear, said support having a portion thereof engaging the trackway and operating to maintain a fixed relationship between the axis of the gear and the axis of the rack.

Il. In combination, a circular rack, a pinion, and an idler gear providing an operative connection between the pinion and rack, the rack having a circular trackway associated therewith, a support bridging the rack and having spaced rollers engaging the traclrway, said idler gear being journalled in said support, and means pivotally mounted on said support and coacting with the pinion for maintaining pitch alignment between the gear and pinion notwithstanding variations in pitch alignment between the pinion and rack.

5. In combination, a circular rack, a pinion and a driving connection therebetween comprising an idler gear simultaneously in mesh with the pinion and rack, a tracliway on the rack, a slotted arm extending across the rack and providing a journal for the gear, rolicr means carried by the arm and engaging the trackway, a. second arm disposed within the slot of the first named arm and mounted for pivotal movement about the axis of the gear, and a support for the pinion, said last named arm being connected to said support whereby the pinion may revolve about the axis of the gear.

6. In combination, a pinion, a circular rack, the pinion being out of mesh with the rack, a traclrway on the rack, two spaced rollers disposed within the trackway, an idler gear engaging the rack and disposed substantially midway between the rollers but on the opposite side of the rack, said idler gear being in mesh with the pinion, means for maintaining a fixed relationship between the axis of the idler gear and rollers, and other means for maintaining a fixed relationship between the axis of the pinion and the gear notwithstanding variations in the relationship between the axis of the pinion and the axis of the rack.

In testimony whereof, I hereunto afiix my signature.

RCBERT WV. KALTENBACH. 

